Information processing apparatus indicating a sleep state and a ready state of printing apparatuses

ABSTRACT

An information processing apparatus serves as a host unit for communicating to a plurality of printing apparatuses via a network. Each of the printing apparatuses includes internal components that are set in a sleep state when power supply to the components is reduced or in a print-ready state when power is supplied to the components. The information processing apparatus includes a unit for requesting status information of each of the plurality of printing apparatuses via the network, a unit for receiving the requested status information from each of the plurality of printing apparatuses, and a unit for identifying each of the plurality of printing apparatuses as being either in the sleep state or in the print-ready state, based on the status information. The information processing apparatus also includes a unit for controlling a display status of each of the plurality of printing apparatuses on a same window, so as to indicate each printing apparatus as being in the sleep state or in the print-ready state, based on respective identification results.

This application is a division of application Ser. No. 08/958,740, filedon Oct. 27, 1997, now U.S. Pat. No. 5,937,148 which is a continuation ofapplication Ser. No. 08/354,116, filed on Dec. 6, 1994 now abandonded.

BACKGROUND OF THE INVENTION

The present invention relates to a printing apparatus having a powersaving function (sleep mode) for suppressing power consumption in anon-printing state, a system having the same, and a method ofcontrolling the printing apparatus.

In recent years, printing apparatuses of this type, e.g., page printersrepresented by laser beam printers have become rapidly widespread.

Generally, an apparatus of this type is constituted by a printercontroller for receiving printing data to generate a printing image andat the same time controlling the entire apparatus, and a printer enginefor actually performing printing. Since the printer engine has a thermalfixing unit, the power consumption is undesirably increased.

For this reason, in a printing standby state, in other words, when apredetermined period of time has elapsed after supply of printing datafrom a host unit (e.g., host computer) is cut off, power to the printerengine, particularly to the thermal fixing unit is stopped, therebyappropriately suppressing the power consumption. That is, this printerhas a sleep mode (or power save mode).

Setting and canceling of the sleep mode are controlled by the printercontroller (CPU in the printer controller). More specifically, uponpower-on, or when a predetermined period of time has elapsed aftercompletion of printing processing, and no further printing data isreceived, power supply to the printer engine is stopped. If printingdata is received in the sleep mode, power supply to the printer engineis resumed.

Although the power consumption can be surely reduced in the sleep modeas compared to an actual printing mode, power supply to the printercontroller never stops. Additionally, the CPU and various circuitsrequiring a large power consumption are connected to the printercontroller through buses. Taking these factors into consideration, nosufficient power saving effect can be obtained yet.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above problem, and thefirst to eighth inventions according to the present invention have astheir object to provide a printing apparatus in which an interfacesection for performing communication processing with a host unit isseparated from a controller section, and the interface section controlsthe power supply states of the controller section and a printer enginesection to control the power supply states of the controller section andthe printer engine section, both of which have a large power loss, suchthat the printing apparatus itself further saves power consumption in asleep state while ensuring a communication state with the host unit.

The first invention according to the present invention comprises aninterface section for performing data communication with a host unit, acontroller section for generating a printing image based on printingdata sent from the host unit through the interface section, an enginesection for performing recording on a recording medium on the basis ofthe printing image from the controller section, and a power supply foralways supplying power to the interface section while a power supplyswitch is in an ON state, wherein the interface section has controlmeans for controlling power supply from the power supply to thecontroller section and the engine section on the basis of data receivedfrom the host unit.

In the second invention according to the present invention, the controlmeans controls power supply such that power supply from the power supplyto the controller section is started upon reception of a predeterminedcommand from the host unit, and power supply from the power supply tothe controller section is stopped upon reception of a predeterminedcommand from the controller section.

In the third invention according to the present invention, the interfacesection has informing means for informing a status of a printingapparatus main body to the host unit.

In the fourth invention according to the present invention, theinterface section communicates with a plurality of host units through anetwork.

In the fifth invention according to the present invention, the host unitpreferentially selects a printing apparatus whose printing apparatusmain body is set in a standby state, which is informed by the informingmeans, before a printing apparatus in a sleep state.

In the sixth invention according to the present invention, when the hostunit recognizes that a plurality of printing apparatuses are set in thestandby state, the host unit sends a command for setting one of theprinting apparatuses in the sleep state to the interface section.

In the seventh invention according to the present invention, theinterface section can be freely attached/detached to/from the printingapparatus main body.

In the eighth invention according to the present invention, theinterface section can be externally connected through an externalinterface port of a printing apparatus main body.

In the first invention according to the present invention, the controlmeans of the interface section controls power supply from the powersupply to the controller section and the engine section on the basis ofdata received from the host unit to limit power supply to the controllersection and the engine section in the sleep state except for powersupply in the interface section, thereby further saving power.

In the second invention, the control means controls power supply suchthat power supply from the power supply to the controller section isstarted upon reception of a predetermined command from the host unit,and power supply from the power to the controller section is stoppedupon reception of a predetermined command from the controller section.In accordance with a command from the host unit, the state of theprinting apparatus can be reversibly switched from the sleep state tothe standby state or from the standby state to the sleep state.

In the third invention, the informing means of the interface sectioninforms the status of the printing apparatus main body to the host unitsuch that the host unit can properly determine the current printerstatus of the printing apparatus.

In the fourth invention, the interface section communicates with thehost unit through a network. Upon reception of a command from any one ofthe host units, power supply to the controller section and the enginesection in the sleep state can be limited except for power supply in theinterface section, thereby further saving power.

In the fifth invention, in accordance with information from theinterface section, the host unit preferentially selects a printingapparatus whose printing apparatus main body is set in the standby statebefore a printing apparatus in the sleep state, thereby determining aprinting apparatus capable of performing printing processing as quicklyas possible.

In the sixth invention, when the host unit recognizes that a pluralityof printing apparatuses whose printing apparatus main bodies are set inthe standby state are present, the host unit sends a command for settingone of the printing apparatuses in the sleep state to the interfacesection. With this operation, regardless of changes in status of eachprinting apparatus, a printing apparatus capable of performing printingprocessing can be determined as quickly as possible while printingapparatuses not subjected to printing are set in the sleep state.

In the seventh invention, the interface section can be freelyattached/detached to/from the printing apparatus main body, therebycoping with expansion or modification of the interface section.

In the eighth invention, the interface section can be externallyconnected through the external interface port of the printing apparatusmain body, thereby externally expanding the function of the interfacesection to a conventional printing apparatus.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the circuit arrangement of a printingapparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view for explaining an example of a printingapparatus shown in FIG. 1;

FIG. 3 is a flow chart showing an embodiment of the first power savingcontrol method of the printing apparatus according to the presentinvention;

FIG. 4 is a flow chart showing an embodiment of the second power savingcontrol method of the printing apparatus according to the presentinvention;

FIG. 5 is a flow chart showing an example of printing data outputprocessing procedures in the printing apparatus according to the presentinvention;

FIG. 6 is a flow chart showing printing processing procedures in a hostcomputer of the third embodiment;

FIG. 7 is a view showing an example of a display screen in the hostcomputer of the third embodiment;

FIG. 8 is a flow chart showing printing processing procedures in thehost computer of the fourth embodiment; and

FIG. 9 is a block diagram of the host computer of the embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment according to the present invention will be described belowin detail with reference to the accompanying drawings.

<Description of Apparatus Arrangement>

FIG. 1 is a block diagram showing the circuit arrangement of a printingapparatus showing an embodiment of the present invention.

Referring to FIG. 1, reference numerals 100-1 and 100-2 denote printingapparatus main bodies. As shown in FIG. 1, the printing apparatuses ofthis embodiment are placed in an environment in which a plurality ofprinting apparatuses are connected to a plurality of host computers130-1 and 130-2.

The printing apparatus main body of this embodiment is mainlyconstituted by a controller section 110 and an engine section 120.

The controller section 110 serves as a printer controller for receivingprinting data, a control command, and the like from an externalequipment, accordingly preparing bit map data in an image memory (notshown), and transferring the data to the engine section 120 as a videosignal. The engine section 120 receives the video signal from thecontroller section 110 and forms a visible image on a sheet surface fromthe video signal (to be described later in detail).

The controller section 110 communicates with the engine section 120 toexternally inform the status of the engine section 120.

The controller section 110 will be described below in detail.

The controller section 110 has a host interface processor (I/Oprocessor; to be referred to as an IOP hereinafter) 111, a CPU 114, aROM 115, a RAM 116, a data bus (bus) 118, and a local bus 119.

As described above, although not illustrated, an image memory fordeveloping a bit map image, an interface to the engine section 120, andan interface to an operation panel (not shown) are also provided on thebus 118.

The IOP 111 transmits/receives data to/from an external apparatus (hostcomputer) and has an intelligence to some extent as described later. Aprogram for interpreting printing data in various printer languages togenerate a bit image, a program for controlling the entire apparatus,and font data are stored in the ROM 115.

The RAM 116 always receives power during the power-ON state of theapparatus main body and is used as a work area of the CPU 114. The RAM116 is also used as a work area for information processing, or used tosave various printing parameters and store the status information of theprinting apparatus.

Data, an address, and a control signal, which are transmitted in thecontroller, flow through the bus 118. The IOP 111 can refer to orwrite-access the RAM 116 through the local bus 119 (not through the CPU114 and the bus 118) which is directly connected to the RAM 116.

Reference numeral 140 denotes a power supply turned on/off by a powersupply switch (not shown). Normally, power having a necessary potentialis always supplied to an interface section 150.

A correspondence between this embodiment and each means of the first toeighth inventions and the function thereof will be described below withreference to FIG. 1.

The first invention has the interface section 150 for performing datacommunication with the host unit 130-1 or 130-2, the controller section110 for generating a printing image based on printing data sent from thehost unit 130-1 or 130-2 through the interface section 150, the enginesection 120 for performing recording on a recording medium on the basisof the printing image from the controller section 110, and the powersupply 140 for always supplying power to the interface section 150during the ON state of the power supply switch. The interface section150 has the control means (IOP 111) for controlling power supply fromthe power supply 140 to the controller section 110 and the enginesection 120 on the basis of data received from the host unit 130-1 or130-2. The IOP 111 controls power supply from the power supply 140 tothe controller section 110 and the engine section 120 on the basis ofthe data received from the host unit 130-1 or 130-2 to limit powersupply to the controller section 110 and the engine section 120 in asleep state except for power supply in the interface section 150,thereby further saving power.

In the second invention, the control means (IOP 111) controls powersupply such that power supply from the power supply 140 to thecontroller 110 is started upon reception of a predetermined command fromthe host unit 130-1 or 130-2, and power supply from the power supply 140to the controller section 110 is stopped upon reception of apredetermined command from the controller section 110. In accordancewith a command from the host unit 130-1 or 130-2, the status of theprinting apparatus main body 100-1 or 100-2 can be reversibly switchedfrom the sleep state to the standby state or from the standby state tothe sleep state.

In the third invention, the interface section 150 has an informing meansfor informing the status of the printing apparatus main body to the hostunit. The informing means (IOP 111) of the interface section 150 informsthe status of the printing apparatus main body to the host unit 130-1 or130-2 such that the host unit 130-1 or 130-2 can properly determine thecurrent printer status of the printing apparatus main body 100-1 or100-2.

In the fourth invention, the interface section 150 communicates with thehost unit 130-1 or 130-2 through a network. Upon reception of a commandfrom any one of the host units 130-1 and 130-2, power supply to thecontroller section 110 and the engine section 120 in the sleep state canbe limited except for power supply in the interface section 150, therebyfurther saving power.

In the fifth invention, in accordance with information from theinterface section 150, the host unit 130-1 or 130-2 preferentiallyselects a printing apparatus whose printing apparatus main body 100-1 or100-2 is set in the standby state before a printing apparatus in thesleep state, thereby determining a printing apparatus capable ofperforming printing processing as quickly as possible.

In the sixth invention, when the host unit 130-1 or 130-2 recognizesthat a plurality of printing apparatuses whose printing apparatus mainbodies 100-1 and 100-2 are set in the standby state are present, thehost unit 130-1 or 130-2 sends a command for setting one of the printingapparatuses in the sleep state to the interface section. With thisoperation, regardless of changes in status of each printing apparatus,the printing apparatus main body 100-1 or 100-2 capable of performingprinting processing can be determined as quickly as possible whileprinting apparatuses not subjected to printing are set in the sleepstate.

In the seventh invention, the interface section 150 can be freelyattached/detached to/from the printing apparatus main body 100-1 or100-2, thereby coping with expansion or modification of the interfacesection 150.

In the eighth invention, the interface section 150 can be externallyconnected through the external interface port (not shown) of theprinting apparatus main body 100-1 or 100-2, thereby externallyexpanding the function of the interface section to a conventionalprinting apparatus.

The engine section 120 of the apparatus of this embodiment will bedescribed below.

FIG. 2 is a sectional view for explaining an example of the printingsection shown in FIG. 1, which corresponds to, e.g., the engine of alaser beam printer.

In the printer of this embodiment, character patterns or fixed formats(form data) can be registered from the host computer.

Referring to FIG. 2, reference numeral 100 denotes an apparatus mainbody. The apparatus main body 100 receives and stores characterinformation (character code), form information, or a macro commandsupplied from the externally connected host computer, and at the sametime prepares a corresponding character pattern or form pattern inaccordance with the information, thereby forming an image on recordingpaper serving as a recording medium.

Reference numeral 700 denotes an operation panel having switches, an LCDdisplay, and the like used for an operation. Reference numeral 701denotes a printer control unit for controlling the entire apparatus mainbody 100 and analyzing character information and the like supplied fromthe host computer.

The printer control unit 701 mainly converts a character patterncorresponding to character information into a video signal and outputsthis video signal to a laser driver 702. The printer control unit 701corresponds to the printer controller section 110 shown in FIG. 1. Thelaser driver 702 is a circuit for driving a semiconductor laser 703,which turns on/off a laser beam 704 emitted from the semiconductor laser703 in accordance with the received video signal. The laser beam 704 isdeflected by a rotary polygon mirror 705 in the right and leftdirections and scanned on an electrostatic drum 706. With thisoperation, an electrostatic latent image such as a character pattern isformed on the electrostatic drum 706. This latent image is developed bya developing unit 707 around the electrostatic drum 706 and thentransferred on recording paper.

As the recording paper, cut sheets are used. The cut sheets are storedin a sheet cassette 708 mounted in the LBP 100, carried into theapparatus by a feed roller 709 and convey rollers 710 and 711, andsupplied onto the electrostatic drum 706. A toner image adhered on theelectrostatic drum 706 by the developing unit 707 is transferred on theconveyed recording paper. Thereafter, the recording paper is conveyedtoward a fixing unit 712, and the toner is fixed. Finally, the recordingpaper is discharged from the apparatus by a discharge roller 713.

FIG. 9 is a block diagram of the host computer shown in FIG. 1.

The host computer has a CPU 91, a memory 92, an input unit 93constituted by a keyboard, a mouse, and the like, a VRAM 94 for storinga display image, a display unit 95 for displaying the image developed bythe VRAM 94, and an interface 96 for sending the printing data to theprinting apparatus described in the above embodiment or receivingvarious information from the printing apparatus. As the interface 96, aprinter interface capable of performing two-way communication or anetwork interface is used.

Programs based on flow charts in FIGS. 5, 6, and 8 (to be describedlater) are stored in the memory 92 and executed by the CPU 91.

<Description of Operation>

The operation of this embodiment in the above arrangement will bedescribed below.

First of all, the operation processing of the CPU 114 of the controllersection 110 of this embodiment will be described with reference to aflow chart in FIG. 3. A program based on this flow chart is stored inthe ROM 115, as a matter of course.

FIG. 3 is a flow chart showing an embodiment of the first power savingcontrol method of the printing apparatus according to the presentinvention. Numbers (1) to (7) denote steps.

When the apparatus is powered on, the initialization processing ofvarious peripheral circuits is performed in step (1). The flow advancesto step (2) to write information representing a printing standby stateat a predetermined address position (to be referred to as a status areahereinafter) in the RAM 116. Note that, upon reception of printing data,an interrupt signal is generated from the IOP 111 to the CPU 114 ofinterface section 150. The CPU 114 receives the printing data in thisinterrupt processing and performs writing processing of the data in areception buffer ensured in the RAM 116.

The flow then advances to step (3) to determine whether the printingdata is stored in the reception buffer. If NO in step (3), the flowadvances to step (4) to determine whether a predetermined period of timehas elapsed in a no-reception state. If it is determined that no data isreceived after that period of time has elapsed, information representinga sleep state is written in the status area of the RAM 116, and at thesame time, a sleep command signal is generated to the IOP 111 ofinterface section 150 (step (5)).

Upon reception of this command, the IOP 111 of interface section 150cuts off power supply to the CPU 114 connected to the bus 118, theremaining units, and the engine section 120 (to be described later indetail). Cutting off of the power itself is performed by, e.g., a relayswitch, and a detailed description thereof will be omitted.

On the other hand, if YES in step (3), the flow advances to step (6) towrite information representing the printing state in the status area.The flow advances to step (7) to perform printing processing on thebasis of the received data.

As a result, three pieces of status information each indicating theprinting standby state, the sleep state, and the printing state (busystate) are stored in the status area.

The control operation by the IOP 111 of interface section 150 shown inFIG. 1 will be described below with reference to FIG. 4.

Unlike the units connected to the bus 118, the IOP 111 and the RAM 116receive power supply during the ON state of the main switch of theapparatus main body regardless of the sleep state.

Control processing performed by the IOP 111 is much simpler than that ofthe CPU 114 as a main unit. The circuits enabled for the operation arealso limited, and the number of types of clocks and the like requiredfor the operation can be largely reduced. For this reason, the powerconsumption can be reduced as compared to a case wherein power issupplied to the controller section 110.

FIG. 4 is a flow chart showing an embodiment of the second power savingcontrol method of the printing apparatus according to the presentinvention. Numbers (11) to (18) denote steps.

In step (11), it is determined whether data is received from the hostcomputer connected to a LAN. If NO in step (11), the flow advances tostep (12) to determine whether a sleep command is received from thecontroller section 110 (CPU 114). This loop of processing is repeatedlyexecuted until data or sleep command is received.

In this loop, if it is determined that a sleep command is received fromthe CPU 114, power supply to all units connected to the bus 118 isstopped in step (13). At the same time, power to the engine section 120is also stopped, and the sleep mode is set.

On the other hand, if YES in step (11), the flow advances to step (14)to acquire information in the status area of the RAM 116 (as describedabove, the RAM 116 receives power supply even in the sleep mode) andreturns the information to the host computer (an ID for specifying thehost computer is stored in the received data) as the data source. If thesleep state is set at that point of time, information representing thesleep state is sent to the host computer.

When the return processing of the status information is completed, theflow advances to step (15) to determine whether the apparatus main bodyis currently set in the sleep state. If NO, i.e., it is determined thatthe printing standby state is set, or the printing state is set on thebasis of the printing data from the host computer, the flow advances tostep (18) to interrupt the CPU 114, thereby causing the CPU 114 toperform interrupt processing (receiving processing).

On the other hand, if YES in step (15), the flow advances to step (16)to determine whether the received data is a printing request command. IfNO in step (16), it is determined that the apparatus requests printingduring the sleep state. Therefore, this request is ignored, and the flowreturns to step (11).

If YES in step (16), the flow advances to step (17) to start powersupply to the controller section 110, thereby canceling the sleep state.

With this operation, the CPU 114 of the controller section 110 startsprocessing based on the above-described flow chart in FIG. 3.

The printing data output processing of the host computer on the LAN willbe described below with reference to the flow chart in FIG. 5.

A program based on the flow chart in FIG. 5 may be the OS or printerdriver of the host computer, or may be executed using an applicationprogram. In this case, an example in which the program is adapted as aprinter driver which operates on the host computer will be described.This program is stored in the memory 92 and executed by the CPU 91 (FIG.9).

FIG. 5 is a flow chart showing an example of printing data outputprocessing procedures in the printing apparatus according to the presentinvention. Numbers (21) to (27) denote steps.

In step (21), a predetermined command is generated to each printerconnected to the LAN to obtain a printer status.

The flow advances to step (22) to determine whether a printer in theprinting standby state is present. If YES in step (22), it is determinedthat the printer can immediately perform printing processing, so thatprinting data is output to the apparatus (step (27)). If a plurality ofprinters are set in the printing standby state, the printing data isoutput to a printer which is detected to be in the printing standbystate first.

On the other hand, if NO in step (22), the flow advances to step (23) todetermine whether a printer in the sleep state is present.

If YES in step (23), a printing request command is generated to theprinter, thereby canceling the sleep state (step (24)) and outputtingthe printing data (step (25)). If a plurality of printers are set in theprinting sleep state, the printing data is output to a printer which isdetected to be in the sleep statefirst.

If NO in step (23), i.e., if it is determined that all printers are setin the printing state (representing that the printing processing forprinting data from another host computer is in progress), informationrepresenting that all the printers on the network are “BUSY” is output(step (26)). The operator is notified at the host computer side that allthe printers are set in the printing state and cannot be currently used.For example, a predetermined message is displayed on the display unit95.

As described above, according to this embodiment, in the sleep state,power supply to the engine section is stopped, and additionally, powersupply to most units of the controller section 110 is also stopped.Therefore, the power consumption can be reduced as compared to the priorart.

In addition, as for the operator of the host computer, since a printerin the printing standby state is preferentially selected before aprinter in the sleep state, the operation environment of the system as awhole can be improved, and at the same time, power can also beeffectively used in the system as a whole.

<Description of Second Embodiment>

In the above embodiment, the CPU 114 of the controller section 110 onthe printing apparatus side determines whether or not the sleep modeshould be set, and actual setting and canceling of the sleep mode isperformed by the IOP 111. The host computer generates a printing requestcommand to cancel the sleep mode.

However, the present invention is not limited to this. For example,setting of the sleep mode may also be designated by the host computer,or status information may be returned only when a status request commandis generated.

In this case, if a host computer requests printing processing, and it isdetermined that two or more printers are in the printing standby state,except for one printer, all remaining printers can be set in the sleepstate.

In addition, if one of a plurality of host computers serves as a printerserver, and printing data generated by each host computer does notrequire immediate printing (a command representing non-urgency is addedto the head of the data), the printing data can be output to only oneprinter.

In the above embodiment, if data is input to the interface section,information representing the sleep state is immediately transferred tothe host computer. However, a control command for performing a similaroperation as the conventional sleep state can also be used. The sleepstate can be set on the printing apparatus side regardless of thecontrol command.

<Description of Third Embodiment>

The third embodiment will be described below.

In the above embodiments, if a printing command is issued from anapplication operating on a host unit (host computer), printers in theprinting standby state (printer which is in a non-printing state, andwhose printer controller section and engine section are powered) ispreferentially selected before printers in the sleep state. If printersin the printing standby state are present, one of them is automaticallyselected, and the printing data is sent to the selected printer.

However, in some cases, it is not preferable if a printer isautomatically selected, and printing data is sent to the selectedprinter.

For example, if a large number of printers are connected to a network,and a selected printer is far from a host computer which sends printingdata, the operator must attend to the printer which is located at adistant location to recover the printing output.

Therefore, it is preferable if an operator can select a printer. Thatis, if a plurality of printers in the same state are present, it ispreferable if a printer can be freely selected therefrom.

In the third embodiment, the above object is realized.

FIG. 6 is a flow chart showing part of the operation of a printer driveroperating on a host computer, which is related to this embodiment. Thisprocessing is started in accordance with a printing command from anoperator. As a matter of course, this program is stored in a memory 92in the host computer as shown in FIG. 9 and executed by a CPU 91.

In step S31, it is determined whether the status is obtained for all theprinters connected to the network through an I/F 96. If NO in step S31,the flow advances to step S32 to generate a status transmission requestcommand to one printer, thereby obtaining the status of the printer.

Note that the printer in the third embodiment has the same arrangementas that described in the first embodiment. Therefore, even whenpredetermined data, e.g., command data for obtaining status informationin this embodiment is sent to a printer, the printer in the sleep stateis not set in the printing standby state. The obtained statusinformation includes the printing standby state, the sleep state, andthe printing state.

When the status is obtained for all the printers by repeatedly executingprocessing in steps S31 and S32, the flow advances to step S33.

In step S33, it is determined whether the icons of all printers aredisplayed on a display 95. If NO in step S33, the flow advances to stepS34 to display an icon according to the status. As for all the printers,icons each corresponding to the status of a corresponding printer aredisplayed.

FIG. 7 is a view showing an example in which a total of four printersare connected to the network. Reference numerals 70 to 73 denote printericons. “PRINTER1 (ID or name on the network)” indicated by the icon 70represents that the printer is currently set in the sleep state. Theicons 71 and 72 represent the printing standby state, and the icon 73represents the printing state. As a result, the operator can easilygrasp the current state of each printer at a glance.

As shown in FIG. 7, when the status is displayed for all the printers,the flow advances to step S35 to wait until one of the printer icons isselected by a pointing device or the like constituting an input unit 93.If one of the printer icons is selected, the flow advances to step S36to determine whether the selected printer icon represents the printingstandby state. If YES in step S36, the flow advances to step S37 tooutput the printing data to the selected printer.

If a printer icon which does not represent the printing standby state isselected, the flow advances to step S38 to determine whether the printerstatus corresponding to the selected printer icon is the sleep state. IfYES in step S38, the flow advances to step S39 to output a printingrequest command (described in the first embodiment) to the printer, andthe printing data is output in step S40.

If it is determined that the selected printer represents neither theprinting standby state nor the sleep state, i.e., the printer iscurrently set in the printing state, the flow advances to step S41 todisplay a message for informing that the selected printer cannot performthe printing operation.

As described above, according to the third embodiment of the presentinvention, when the host computer issues a printing command, the currentstatus of each of a plurality of printers is visually indicated, and oneof them is selected, thereby performing the printing operation in theprinter desired by the operator.

If a large number of printers in the printing standby state aredisplayed, a pointing device or the like may be used to send a commandfor setting the printers in the sleep state.

<Description of Fourth Embodiment>

In the third embodiment, an example has been described in which alloperable printers (printers at least whose main switches are in an ONstate) on the network are displayed. That is, printers in the printingstandby state and printers in the sleep state are simultaneouslydisplayed together. Regardless of presence of printers in the printingstandby state, a printer in the sleep state can be operated to performthe printing operation. From the viewpoint of a user interface, thismethod is excellent because the closest one of printers capable ofprinting can be selected. On the other hand, since a printer in theprinting standby state is not always positively preferentially selected,the power consumption of the system as a whole cannot be suppressed.

In the fourth embodiment, when the printing operation is to beperformed, an icon list of printers in the printing standby state isdisplayed, and a printer to which printing data is output is freelyselected from these printers. If no printer in the printing standbystate is present, a printer can be freely selected from printers in thesleep state.

FIG. 8 is a flow chart showing the operation processing of a printerdriver on a host computer in a host unit of the fourth embodiment. Theprinter has the same arrangement as that of the first embodiment.Additionally, a program corresponding to this flow chart is stored in amemory 92 and executed by a CPU 91.

In step S51, it is determined whether the status is obtained for all theprinters connected to the network. If NO in step S51, the flow advancesto step S52 to generate a status transmission request command to oneprinter, thereby obtaining the status of the printer.

When the status is obtained for all the printers, the flow advances tostep S53 to determine whether a printer in the printing standby state ispresent.

If YES in step S53, an icon corresponding to the printer in the printingstandby state is displayed on a display unit 95 of the host computer insteps S54 and S55. When at least one printer is set in the printingstandby state, the icons of printers in the sleep state are notdisplayed.

If NO in step S53, the flow advances to step S56 to determine whether aprinter in the sleep state is present. If YES in step S56, an iconcorresponding to the printer in the sleep state is displayed in stepsS57 and S58.

In either case, if printer icons are displayed, the flow advances tostep S59 to select one of the displayed icons using a pointing device ofan input unit 93.

In step S60, the status of the printer corresponding to the selectedicon is determined. If a printer in the sleep state is selected, theflow advances to step S61 to output a printing request command to theprinter, thereby setting the printer in the printing standby state.

In step S62, printing data is output to the printer, thereby ending thisprocessing.

If no printer in the printing standby state and in the sleep state ispresent, a message for informing that the printing operation cannot beperformed is displayed in step S63, thereby ending this processing.

As described above, according to the fourth embodiment, printers in theprinting standby state are preferentially selected, and a desiredprinter can be selected from the printers in the printing standby state.Therefore, the power consumption of the system as a whole can besuppressed as compared to the third embodiment.

In the third embodiment, an error message is displayed when a printingcommand is generated to a printer in the printing state. In the fourthembodiment, an error message is displayed when no printer in theprinting standby state and in the sleep state is present.

However, when a printing operation is to be performed through thenetwork, the printing operation is performed through a printer server,as is well known, and the printing data is generally supplied to theprinter server. Therefore, if a printer server is used, the printingdata may be sent to the printer server. Even if the desired printer isset in the printing state, the printing data may be set in a printingqueue. In this case, however, the operator must realize that theprinting output is going to be obtained with a slight delay.

In the first to fourth embodiments, the host unit (host computer)directly outputs a status information transmission command to theprinter. However, if a printer server is used, the command may be outputto the printer server. Upon reception of the command, the printer serveracquires the current status of the corresponding printer and informs thestatus to the inquiring host computer.

In the above embodiments, the interface section is incorporated in theprinting apparatus. However, the present invention can also be appliedto an interface section which can be externally expanded.

In a recent printing apparatus, particularly in a printing apparatusdesigned for use in a network environment, a plurality of interfacecircuits are often provided. In addition, to cope with a larger numberof interfaces, some printing apparatuses have an expandable interfacecircuit.

As described above, when the interface circuit in the present inventionis externally expanded, power savings control is enabled in varioustypes of interfaces. The type of an interface can be changed in thefuture only by changing the expandable interface circuit applicable tothe present invention.

In addition, in the above embodiments, a laser beam printer isexemplified as a printing apparatus. However, these embodiments can alsobe applied to another apparatus using an electrophotography system suchas an LED printer, as a matter of course. Furthermore, the presentinvention can also be applied to, e.g., a wire-dot or thermal transfersystem although no dramatic effect cannot be expected as for reductionin power consumption. The effect is increased especially in an officehaving relatively large power consumption.

The above embodiments refer to only the sleep state of the printingapparatus. However, the present invention can be applied to a hostcomputer having the sleep state. If the present invention is applied toanother network resource, lower power consumption control of the networkas a whole can be performed.

If the present invention is applied to the host computer, the effect ofreduction of power consumption in the host computer can be obtained.Additionally, when a computer load is used to manage the statusinformation, an effect of dispersing the computer load can also beobtained.

Therefore, the present invention may be applied to a system constitutedby a plurality of equipments or an apparatus constituted by oneequipment. The present invention can also be applied to a system orapparatus to which a program is supplied, as a matter of course.

As has been described above, according to the above embodiments,although the arrangement of the apparatus is slightly complicated ascompared to the prior art, power consumption in the sleep state can bereduced as compared to the prior art. In consideration of the networkenvironment, when this control method is applied to other resources, thenetwork resource can be efficiently utilized.

As described above, according to the first invention according to thepresent invention, the control means of the interface section controlspower supply from the power supply to the controller section and theengine section on the basis of data received from the host unit to limitpower supply to the controller section and the engine section in thesleep state except for power supply in the interface section, therebyfurther saving power.

According to the second invention, the control means controls powersupply such that power supply from the power supply to the controllersection is started upon reception of a predetermined command from thehost unit, and power supply from the power to the controller section isstopped upon reception of a predetermined command from the controllersection. In accordance with a command from the host unit, the state ofthe printing apparatus can be reversibly switched from the sleep stateto the standby state or from the standby state to the sleep state.

According to the third invention, the informing means of the interfacesection informs the status of the printing apparatus main body to thehost unit such that the host unit can properly determine the currentprinter status of the printing apparatus.

According to the fourth invention, the interface section communicateswith the host unit through a network. Upon reception of a command fromany one of the host units, power supply to the controller section andthe engine section in the sleep state can be limited except for powersupply in the interface section, thereby further saving power.

According to the fifth invention, in accordance with information fromthe interface section, the host unit preferentially selects a printingapparatus whose printing apparatus main body is set in the standby statebefore a printing apparatus in the sleep state, thereby determining aprinting apparatus capable of performing printing processing as quicklyas possible.

According to the sixth invention, when the host unit recognizes that aplurality of printing apparatuses whose printing apparatus main bodiesare set in the standby state are present, the host unit sends a commandfor setting one of the printing apparatuses in the sleep state to theinterface section. With this operation, regardless of changes in statusof each printing apparatus, a printing apparatus capable of performingprinting processing can be determined as quickly as possible whileprinting apparatuses not subjected to printing are set in the sleepstate.

According to the seventh invention, the interface section can be freelyattached/detached to/from the printing apparatus main body, therebycoping with expansion or modification of the interface section.

According to the eighth invention, the interface section can beexternally connected through the external interface port of the printingapparatus main body, thereby externally expanding the function of theinterface section to a conventional printing apparatus.

Therefore, power supply to the controller section and the printer enginesection, both of which have a large power loss, is controlled while theprinter apparatus itself further reduces the power consumption in thesleep state, and at the same time, the communication state with the hostunit can be ensured.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

What is claimed is:
 1. An information processing apparatus which servesas a host unit for communicating to a plurality of printing apparatusesvia a network, each of the printing apparatuses including internalcomponents that are set in a sleep state when power supply to thecomponents is reduced or in a print-ready state when power is suppliedto the components, said information processing apparatus comprising:request means for requesting status information of each of the pluralityof printing apparatuses via the network; receiving means for receivingthe status information from each of the plurality of printingapparatuses requested by said request means; identifying means foridentifying each of the plurality of printing apparatuses as beingeither in the sleep state or in the print-ready state based on thestatus information; and user-interface means for controlling a displaystatus of each of the plurality of printing apparatuses on a same windowso as to indicate each printing apparatus as being in the sleep state orin the print-ready state, based on a respective result of identificationof said identifying means.
 2. The apparatus according to claim 1,further comprising designation means for designating one of theplurality of printing apparatuses to which printing data is to beoutputted by using a pointing device to designate a respective symbolwhile symbols representing the statuses of the plurality of printingapparatuses are displayed by said user-interface means.
 3. The apparatusaccording to claim 1, wherein each of said symbols is a visual icon forindicating the status of the respective printing apparatus.
 4. Theapparatus according to claim 2, wherein said user-interface meansdisplays the symbols as icons, and wherein said designation meansdesignates the one printing apparatus to which printing data is to beoutputted by selecting the respective icon using the pointing device. 5.The apparatus according to claim 2, further comprising output means foroutputting print data to a server which manages the printing apparatusdesignated by said designation means.
 6. An information processingapparatus which serves as a host unit for communicating to a pluralityof printing apparatuses via a network, each of the plurality of printingapparatuses being in a printing state or in a print-ready state, saidinformation processing apparatus comprising: request means forrequesting status information of each of the plurality of printingapparatus; receiving means for receiving the status information fromeach of the plurality of printing apparatuses requested by said requestmeans; identifying means for identifying each of the plurality ofprinting apparatuses as being either in the printing state or in theprint-ready state based on the status information; and user-interfacemeans for controlling a display of icons that indicate visually thestatus of each of the plurality of printing apparatuses so as toindicate each printing apparatus as being in the printing state or inthe print-ready state, on the basis of a result of identification ofsaid identifying means.
 7. The apparatus according to claim 6, furthercomprising designation means for designating one of the plurality ofprinting apparatuses to which printing data is to be outputted by usinga pointing device to designate a respective icon while iconsrepresenting the statuses of the plurality of printing apparatuses aredisplayed by said user-interface means.
 8. The apparatus according toclaim 7, further comprising output means for outputting print data to aserver which manages the printing apparatus designated by saiddesignation means.